Value and limits of endorectal ultrasonography for preoperative staging ofrectal carcinoma

In rectal cancer, the depth of tumor infiltration and metastatic involvemen t of lymph nodes are important prognostic factors. Endosonography of the re ctum, combining the advantages of both endoscopy and sonography,provides in formation not available from other imaging diagnostic techniques. From Janu ary 1989 to December 1997, 85 patients affected by rectal carcinoma were su bmitted to preoperative evaluation with endorectal ultrasonography. In 75 c ases the results obtained with the endosonography were compared to the hist ology of the resected specimens. Overall accuracy in staging depth of infil tration was 90.7%. Overstaging occurred in 4% of patients, whereas understa ging occurred in 5.3%. In staging lymph nodal involvement, overall accuracy was 76%, sensitivity was 69.8%, specificity was 84.4%, positive predictive value was 85.7%, and negative predictive value was 67.5%. Endorectal ultra sound is a safe and accurate diagnostic method for staging both tumor invas ion and lymph node metastatic involvement, and for selecting an appropriate surgical strategy in patients affected by rectal cancer.